Uncertain Times for DefenseADCs and DACs Penetrate Sacred Ground
By Barry Manz

The impact of converting analog signals to digital form is one of the greatest advances the electronics industry has ever achieved.

Defense News

Northrop Grumman MMICs Speed AEHF Production
Northrop Grumman has fabricated more than 36,000 MMICs covering frequencies from 300 MHz to 300 GHz for the U.S. Air Force's fifth and sixth Advanced Extremely High Frequency (AEHF) satellites, speeding production of both spacecraft, according to Space Daily.

Article Highlights China Cruise Missile Threat
While the world focuses on China’s ballistic missiles, the country is rapidly developing advanced capabilities for its cruise missiles, according to The National Interest. This is occurring at the same time the U.S. Navy has limited the type and quantity of its own anti-ship cruise missiles, according to the article.

Iran Claims It Reverse-Engineered RQ-170 UAV
Iran says it has copied announced on Sunday that it has copied an RQ-170 Sentinel UAV that it says the country "commandeered" in 2011, after his allegedly being "brought down by the Iranian Armed Forces' electronic warfare unit" in December 2011, according to Iran's Tasnim News Agency. That Iran captured the UAV is not in doubt: U.S. President Barack Obama asked Iran sent to return it after it was captured.

Israeli Navy Gaining Greater Capabilities
The Israel Navy has begun a program to enhance its sea-to-surface missile capabilities, a senior naval source told The Jerusalem Post, who said that the efforts were part of a planned program to increase the role of the navy in integrated warfare capabilities.

House House to Keep A-10, Other Programs
The House Armed Services Committee (HASC) is opted to fund a broad array of projects and has stated its goal of protecting every possible defense system. For example, the committee left the Lockheed Martin F-35 Joint Strike Fighter largely intact and up the funding for Boeing's EA-18G Growler electronic attack aircraft.

EW Development Key Element of 2015 Budget
The proposed defense budget may be leaned out but electronic warfare will receive considerable funding as the need for it is growing, according to an interesting story in the LA Times.

Insight into Hypersonic Weapons
An article in The Interpreter published by the Lowy Institute for International Policy contains an interview by Harry Kazianis, a non-resident senior fellow at the China Policy Institute (University of Nottingham) with John Stillion, a senior fellow at the Center for Strategic and Budgetary Assessments (CSBA) into the workings of hypersonic weapons.

September 2013

Spectrum Management: How We Got Here

The way that services in the U.S. have been allocated portions of the electromagnetic spectrum is difficult to understand by simply looking at a standard spectrum chart. In addition to being almost incomprehensibly dense, some services are allocated resources in multiple bands rather than together in a single band. There are solid and some less sold reasons why this has occurred, and to gain some insight into how it all came about, it helps to look at some of the major regulatory events that have taken place since the turn of the 20th Century. It is a story of an incremental process of regulation driven by technology, politics, and financial interests.

In the early 1900s, the only use of the electromagnetic spectrum was for radiotelegraphy for maritime communications, but this business rapidly grew throughout the world, driven primarily by the Marconi Wireless Telegraph Company and later by others. There was at this point no need for spectrum management or regulation but the rapid growth of radiotelegraphy and the lack of regulation made the situation like the Wild West, as Marconi brooked no competition to its preeminent position in radiotelegraphy equipment.

Marconi set up numerous shore stations at major ports throughout the world and instructed its employees not to handle traffic that originated from equipment other than its own. This worked until 1902 when a single event made governments realize that Marconi’s monopoly could no longer be tolerated. Having just ended what was apparently a pleasant visit to America, Prince Henry of Prussia sent a message to President Roosevelt thanking him for the hospitality. It never got there. A dutiful Marconi equipment operator refused to send it based on the company’s iron-clad policy.

The now highly-agitated and embarrassed prince told his brother Kaiser Wilhelm about this development and the German government quickly proposed an international conference to discuss regulating maritime communications. This first international conference resulted in a proposal to make all stations accept messages form any ship regardless of what equipment was used to send it. The cooperation evidenced in this conference lead to another one in 1906 at which the U.S. Navy effectively debunked the claim by Marconi that equipment from different manufacturers was incompatible, and all participants agreed to be “vendor neutral”. An international bureau was created in Berne, Switzerland, to house and disseminate information about all systems currently deployed and the location of wireless stations in each country. This was arbuably the first step toward creation of today’s International Telecommunications Union (ITU), to which at this early date was added the extension “Radiocommunications” (ITU-R) as it was then the only type of telecommunications available.

America played a major role in the drive toward more detailed regulations although progress in getting laws passed was sluggish. However, once again a single event led to rapid change: the sinking of the Titanic in 1912 and the key role that radiotelegraphy played in saving lives. Almost immediately thereafter legislators signed a law regulating emissions characteristics and distress calls along with identifying specific frequencies for government use. Licensing was to be handled by the Secretary of Commerce and Labor. Another international conference was scheduled shortly thereafter but was delayed until 1927 by World War I.

In the intervening years, radiotelegraphy had been joined by broadcast radio, which complicated matters, and President Warren G. Harding directed then Secretary of Commerce Herbert Hoover to find a way to accommodate it. The result was a recommendation on how spectrum should be allocated, the first real attempt at spectrum management. It was nonetheless only a recommendation so no one was legally bound to uphold it, which they often did not. When a station in Chicago requested a channel and the commerce department rejected it, the station went on the air anyway.

This prompted a lawsuit by the government, which to its embarrassment, it lost. The court ruled that the government could not reject a request from a legitimate entity, which effectively meant that the government had no control over spectrum use. The timing of this decision could not have been worse, as an international conference on spectrum regulation was to take place in Washington that year.

Not surprisingly, the Radio Act of 1927 was quickly drawn up and signed into law, creating a commission with the authority to license stations, allocate frequencies dedicated to specific services, assign channels to stations, and control transmitted power. This was obviously the most comprehensive telecommunications law the country had ever enacted, and it set the pace for even further regulations.

The 1927 International Radio Conference in Washington then produced the first actual regulations for spectrum management that included allocation by type of service – fixed, mobile, broadcast, and amateur (which is all there was at the time). All countries would have the right to use these frequencies for their respective purposes. Modifications continued to be made to spectrum management policies (such as the addition of aviation) in subsequent conferences and the globe was split up into regions, which still exist today.

The burgeoning federal bureaucracy caused a proliferation of government agencies that controlled their own frequency allocations. The landmark Communications Act of 1934 solved that and went much further, creating a Federal Communications Commission that would report to Congress rather than the executive branch (a key distinction) and would oversee the entire government user community. However, the President, through the Department of Commerce, retained the responsibility for federal spectrum management, a situation that remains in place today. That is, the FCC manages spectrum use for commercial, state, and local government agencies, and the commerce department manages the spectrum for federal government agencies.

By this time (1934), nearly four decades had passed since radiotelegraphy appeared, and technology had significantly advanced and services using the spectrum had skyrocketed. Thus began the first major interference problems that today have become an issue to be reckoned with. The U.S. proposed rules that would create the International Frequency Regulation Board (IFRB) whose responsibility was to keep track of frequency assignments and make recommendations on spectrum usage based on their potential for interference both within the U.S. and internationally.

There is a very long list of other regulations regarding spectrum management changes that have been adopted since then, including the creation in 1978 of the National Telecommunications and Information Administration (NTIA) that has played a key role in proposing solutions to problems arising from advances in technology and introduced the concept of spectrum auctions. The ITU became a massive international regulatory force, was placed under the wing of the United Nations, and today has 193 member states and about 700 “sector” members.

From the viewpoint of spectrum management, there is hardly any resemblance to conditions of even 30 years ago. Wireless transmission is now almost exclusively digital, applications have multiplied, and any activity that can more effectively be conducted without wires either now is or soon will be “wireless-enabled”. More regulations to follow.


Download Digital Edition

MMD March 2014

Previous issues click here

Current Articles

Cut the Defense Budget? Sure, No Worries
The Obama administration and the President himself have always believed that the Department of Defense is like every other government agency: in tough economic times its budget must be cut like everything other agency.

HF SIGINT: A Return from the Dead?
Winston Churchill’s assessment of Ultra in winning World War II was joined by those of then-General Dwight D. Eisenhower who credited it as “decisive” and later by British intelligence official historian Sir Harry Hinsley, who flatly stated that it shortened the length of the war by “not less than two years and probably by four years.

Digital Technology is Removing the RF-to-Digital Divide
While defense systems are far from the first to realize the benefits of digital technology, they nevertheless obtain extraordinary benefits from it. However, one of greatest challenges remains the transformation of analog signals captured over the air into digital data streams--without using large amounts of intervening RF and microwave hardware.

The CDAA Antenna and the Wullenweber
A CDAA (Figure 1) of which the Wullenweber is a type, consists of a group of omnidirectional antennas symmetrically spaced about the periphery of a circular reflector screen. The location of each antenna with respect to the screen and to the adjacent antenna is such that by using a suitable antenna output scanning system, the array provides high unidirectional gain in all directions of azimuth.

Home | About Us | Archives | Editorial Submissions | Media Kit (PDF) | Events | Subscribe/Renew | Contact Us
Copyright © 2014 Octagon Communication Inc. DBA MPDigest / MPDigest.com, All Rights Reserved.
Privacy Policy | Site Map